It has already been announced that Ruby Sunday, played by Mollie Gibson, in the Doctor Who season that will start to be streamed on May 11th on the BBC iPlayer and Disney+ will be leaving the series before the end of the second season, therefore how many time during the first season will Ruby Sunday die?
A death is classed as Ruby being physically killed whether the Doctor reverses that death or not (cf Rory Williams)
This question will resolve at the end of transmission of the first season on BBC One (linear)
@HarryHayfield Christmas Special: The Church on Ruby Road: When infant Ruby is taken by the goblins, in that altered timeline she is eaten, and even though it is reversed by the Doctor, this counts as Death number one
@HarryHayfield Episode One: Space Babies. After stepping onto a butterfly, the being known as Ruby Sunday no longer exists, until the Doctor enfuses the butterfly with regeneration energy. I am counting this as a death as Ruby Sunday does not exist for the duration.